MURRAY — They were best friends who had known each other since the fourth grade and they lived right across the street from each other.

Monday, two families were grieving and asking questions that police say may never be answered following the tragic shooting deaths of Andrew Nelson, 15, and Ashton Peck, 13, over the weekend.

"I'm just so confused about this whole thing because two young men lost their lives and that's the whole sad part about the whole thing, that no one will ever know what happened," said Ashton's father, Michael Peck.

"You feel angry, you feel sadness. But when you come down to the truth, we're talking about two young adults who didn't get to live a long life at all. And that's the whole sad part about the whole thing."

"Both individuals died of a single gunshot wound each," said Murray police detective Jeff Maglish.

The teen's mother and stepfather had left the house for less than an hour to run an errand. They discovered the boys when they returned, said Maglish. Ashton, who turned 13 a little over a week ago, was declared dead at the scene. Andrew was hospitalized but died Sunday after he was taken off life support.

"Both of these families are grieving together. These boys were good friends. These boys were loved greatly by their parents and just can’t overstate how tragic this is for everybody," said Douglas Thayer, the attorney for Andrew's family.

Whether the deaths of Andrew and Ashton were the result of a suicide pact, an argument or a tragic accident, investigators fear they may never know.

"Unfortunately, I don't know if we'll ever have that answer. As for any type of note or anything that would lead us to believe it was some kind of suicide, those do not exist. We do not have any notes or anything like that. They were the only two individuals in the house at the time of the incident," Maglish said.

The boys were found in two different parts of the house, according to the detective. A single handgun was recovered. The gun came from inside the house but did not belong to either of the two boys, he said.

Ashton was discovered first, and then Andrew in another bedroom, Peck said.

Investigators have been trying to recreate the sequence of events.

"We do know we're not looking for any additional suspects. So we do believe everything came from within the household," Maglish said. "We're looking at every angle possible. As far as we know, they were best of friends and there weren't any current arguments going on."

Both Peck and Thayer confirmed that the families had not heard any talk of suicide among the boys.

"The family is very involved with police. They’ve been cooperating in every respect to try and figure out what happened. This is extremely puzzling to them as you can imagine," Thayer said.

Friends of the two boys held a candlelight vigil on their street Sunday night. A makeshift memorial for the two also started to spring up that evening.

"He was a great kid. He loved life. He loved his family. Very outgoing. He had a lot of friends," Peck said of his son. "The fact of not knowing exactly what happened will eat everybody. It's like a nightmare you wake up to and it won't go away."

Peck said Ashton and Andrew "were like peas and carrots" and did everything together. He called them both "good kids" who loved riding skateboards together.

"The whole thing is just really, really confusing," he said.

On Monday, grievance counselors were helping students and staff at Murray High School, where Andrew was a sophomore, and at Riverview Junior High, where Ashton was a seventh-grader. Counselors were also at Grant Elementary, where Ashton attended school last year.

"I just broke down crying because I knew them both really good," said Hallee Maxwell, a ninth-grader at Riverview. "You will never forget them because they were always outstanding. I think it was an accident mostly because they were really good friends so I don’t think it was on purpose."

"They were always really happy and always trying to make you happier, so I just hope they are remembered for who they are," said Chelsey Drury, a ninth-grade student at Riverview. "It's always tough to hear of a death in your school and know that they’re not here anymore. They seemed pretty happy. They were always really encouraging and seemed to be happy."